The perfume impact that a particular perfume will have on the consumer when, for example, washing oneself with a personal wash bar, is known as the perfume “bloom”. Enhanced perfume bloom is a major attribute to overall fragrance liking and can therefore potentially improve consumer appreciation of perfume performance when washing.
There is a number of references relating to perfume bloom during product use.
U.S. Pat. No. 6,998,382 to Yang et al. discloses a process for making perfume containing surfactant compositions having perfume burst and enhanced perfume deposition when diluted. U.S. Pat. No. 6,858,574 to Yang et al. also discloses a process for making perfume containing surfactant compositions having perfume bloom when diluted, as well as formulation factors which affect this process. Neither reference discloses a method of enhancing bloom using low TFM bars having starch polyol structuring system.
The following references to Proctor & Gamble are generally related to blooming perfume in various product forms as noted:                1) EP 1 656 441 (soap bars);        2) U.S. Pat. No. 7,030,068 (automatic dishwashing);        3) U.S. Pat. No. 6,194,362 (glass cleaning composition);        4) U.S. Publication No. 2007/0280976 (multi-phase personal care composition); and        5) EP 88846 B1 (toilet bowl detergent).        
The above references disclose the selection of perfume ingredients for blooming according to HIA (High Impact Accord), which in turn is defined by factors including boiling point, oil/water partition coefficient (CLogP), and the odor detection threshold. EP 1656441, for example, discloses encapsulation of blooming perfume ingredients according to HIA in soap bars. Encapsulation materials comprise starch, cyclodextrin, zeolite, silica or mixtures thereof.
Again, a method of enhancing bloom by selecting and utilizing perfume in the low total fatty matter, extruded bars of the invention comprising a starch polyol structuring system is not disclosed.
In general, when the predominant surfactant in the personal washing bar is fatty acid soap, a reduction in surfactant is commonly expressed as a reduction in “Total Fatty Matter” or TFM. The term TFM is used to denote the percentage by wt. of fatty acid and triglyceride residues present in soaps without taking into account the accompanying cations. The measurement of TFM is well known in the art. A “low” TFM bar is typically one which will have <70%, preferably <65%, more preferably <60% and even more preferably <55% by wt. TFM.
There are references which do disclose generally extruded bars with low TFM and comprising structuring systems like those of the invention. GB Application No. 806340.6 to Leopoldino (Unilever), filed Apr. 8, 2008, for example, discloses low TFM extrudable soap bar compositions which include starch, polyols and optionally water insoluble particles. Perfume is an optional ingredient which is recited in a long list of many possible options and there is no disclosure or suggestion that there is any benefit to using perfume in such bar compositions relative to any other bar compositions.
As noted, applicants have filed co-pending Great Britain Application No. 0806340.6 to Leopoldino et al., entitled “Extruded Soap Bars Comprising a Composite Starch-Polyol Structuring System”. Applicants have also filed Great Britain Application No. 0901953.0 to Canto et al., entitled “Low TFM Soap Bars Employing a Starch Polyol Structuring System”.
Again, neither reference discloses or recognizes the unexpected perfume bloom which occurs when using low TFM starch-polyol bars relative to other bar compositions.
Quite unexpectedly, however, applicants have found that, when perfume is used in such specific, low TFM, starch-polyol structured systems (comprising, for example, 5 to 30% preferably 6 to 25% by wt. polyol), there is found enhanced perfume blooming when compared to, for example, the perfume bloom effect of the same perfume used in soap bars having >60% by wt. fatty acid soap.
While not wishing to be bound by theory, applicants believe that the high level of polyol (required for reducing TFM using starch-polyol structuring system) is typically inhibiting (or suppressing) perfume headspace over bars because the polyols are good solvents for the perfume oils. However, it is believed, this “suppression” effect of polyols on perfume headspace disappears when the bar is diluted by water. Thus, quite unpredictably, the use of high polyol level in the low TFM starch-polyol system ends up enhancing bloom on dilution apparently because the “suppressed” perfume (suppressed by high polyol) is released on dilution. In higher TFM bars (>60% fatty acid soap), the same enhancement is not observed.